The use of access terminals such as cellular telephones, personal digital assistants, pagers, or portable computers has become an increasingly popular means of communicating with others, accessing information, conducting business, and performing myriad other activities. Access terminals typically communicate with radio access networks (RANs). These access terminals and RANs typically communicate with each other over a radio frequency (RF) air interface using any of a number of communication protocols, such as evolution data optimized (EV-DO), WiMax, code division multiple access (CDMA), and/or other protocols.
In a typical RAN, an area is divided geographically into a number of cells and sectors, each defined by a RF radiation pattern from a respective base station in the RAN. Within each sector (or cell), the base station's RF radiation pattern provides the RF air interface over which access terminals may communicate with the RAN. In turn, the RAN may communicate with one or more other networks, such as the Public Switched Telephone Network (PSTN) or the Internet. As such, when an access terminal is positioned within a coverage area of the RAN (e.g., in a given sector or cell), the access terminal can communicate with entities on the other networks via the RAN.
The RF air interface of any given sector (or cell) in the RAN is typically divided into a plurality of channels for carrying communications between access terminals and the RAN. For example, the RF air interface may include a plurality of forward-link channels, such as pilot channels, sync channels, paging channels, and forward-traffic channels, for carrying communications from the RAN to access terminals. As another example, the RF air interface may include a plurality of reverse-link channels, such as access channels and reverse-traffic channels, for carrying communications from the access terminals to the RAN. Depending on the wireless technology used, the air interface can be divided into these channels through code division multiplexing (with each channel defined by modulation with one or more specific codes), time division multiplexing (with each channel defined as one or more recurring segments of time), frequency division multiplexing (with each channel defined by modulation with one or more specific frequencies), and/or some other mechanism.